1. Field of the Invention
The present invention is related to a fan and particularly to a fan employed on a radiator.
2. Brief Description of the Related Art
Referring to FIGS. 1 and 2, the conventional fan includes a fan blade wheel 11 and a fan frame 12. The fan blade wheel 11 provides a hub 111 with a plurality of fan blades 112 extending radially from the circumferential side of the hub 111 as shown in FIG. 3. The fan frame 12 has four lateral side walls and an inner wall with an air inlet 123 and an air outlet 124. A fan blade wheel seat 121 is provided at the center of the air outlet 124. The air outlet 124 is mounted to a heat generating component 13 with fasteners 126 passing through engaging holes 125 at the four corners of the fan frame 12 such that the fan wheel 11 and the fan frame 12 are attached to the heat generating component 13.
The hub of the conventional fan device does not provide a guiding flow part except fan blades 112 so that the fluid flow moves toward all directions after passing through a space between every two neighboring fan blades once the fluid moves into the fan blade wheel 11. As a result, fluid pressure of the fluid moving toward the outlet 124 becomes getting lower due to resistance of the outer surface of the hub 111 and it is easy to result in reversed flow at low pressure area of the back of the hub 111 to affect heat dissipation.